bt: uplink: subscribe to indications if node supports it

Signed-off-by: Sam Friedman <sam@golioth.io>

Author: sam-golioth

gateway/src/bt/uplink.c

@@ -21,19 +21,8 @@
 #include <zephyr/logging/log.h>
 LOG_MODULE_REGISTER(uplink_gatt);
 
-/* Callback for handling BLE GATT Uplink Response */
-static uint8_t tf_uplink_read_cb(struct bt_conn *conn,
-                                 uint8_t err,
-                                 struct bt_gatt_read_params *params,
-                                 const void *data,
-                                 uint16_t length)
+static uint8_t handle_uplink_payload(struct bt_conn *conn, const void *data, uint16_t length)
 {
-    if (err)
-    {
-        LOG_ERR("Failed to read BLE GATT %s (err %d)", "Uplink", err);
-        return BT_GATT_ITER_STOP;
-    }
-
     bool is_first = false;
     bool is_last = false;
     const void *payload = NULL;
@@ -56,7 +45,7 @@ static uint8_t tf_uplink_read_cb(struct bt_conn *conn,
     int ret = pouch_uplink_write(node->uplink, payload, payload_len, is_last);
     if (ret)
     {
-        LOG_ERR("Failed to write to pouch (err %d)", err);
+        LOG_ERR("Failed to write to pouch (err %d)", ret);
         bt_conn_disconnect(conn, BT_HCI_ERR_REMOTE_USER_TERM_CONN);
         return BT_GATT_ITER_STOP;
     }
@@ -69,6 +58,29 @@ static uint8_t tf_uplink_read_cb(struct bt_conn *conn,
         return BT_GATT_ITER_STOP;
     }
 
+    return BT_GATT_ITER_CONTINUE;
+}
+
+/* Callback for handling BLE GATT Uplink Response */
+static uint8_t tf_uplink_read_cb(struct bt_conn *conn,
+                                 uint8_t err,
+                                 struct bt_gatt_read_params *params,
+                                 const void *data,
+                                 uint16_t length)
+{
+    if (err)
+    {
+        LOG_ERR("Failed to read BLE GATT %s (err %d)", "Uplink", err);
+        return BT_GATT_ITER_STOP;
+    }
+
+    err = handle_uplink_payload(conn, data, length);
+
+    if (BT_GATT_ITER_STOP == err)
+    {
+        return err;
+    }
+
     err = bt_gatt_read(conn, params);
     if (err)
     {
@@ -79,6 +91,20 @@ static uint8_t tf_uplink_read_cb(struct bt_conn *conn,
     return BT_GATT_ITER_STOP;
 }
 
+static uint8_t tf_uplink_indicate_cb(struct bt_conn *conn,
+                                     struct bt_gatt_subscribe_params *params,
+                                     const void *data,
+                                     uint16_t length)
+{
+    if (NULL == data)
+    {
+        LOG_DBG("Subscription terminated");
+        return BT_GATT_ITER_STOP;
+    }
+
+    return handle_uplink_payload(conn, data, length);
+}
+
 void gateway_uplink_start(struct bt_conn *conn)
 {
     struct golioth_node_info *node = get_node_info(conn);
@@ -89,21 +115,40 @@ void gateway_uplink_start(struct bt_conn *conn)
     if (node->uplink == NULL)
     {
         LOG_ERR("Failed to open pouch uplink");
-        bt_conn_disconnect(conn, BT_HCI_ERR_REMOTE_USER_TERM_CONN);
+        (void) bt_conn_disconnect(conn, BT_HCI_ERR_REMOTE_USER_TERM_CONN);
         return;
     }
 
-    struct bt_gatt_read_params *read_params = &node->read_params;
-    memset(read_params, 0, sizeof(*read_params));
-
-    read_params->func = tf_uplink_read_cb;
-    read_params->handle_count = 1;
-    read_params->single.handle = node->attr_handles[GOLIOTH_GATT_ATTR_UPLINK].value;
-    int err = bt_gatt_read(conn, read_params);
-    if (err)
+    if (node->attr_handles[GOLIOTH_GATT_ATTR_UPLINK].ccc)
     {
-        LOG_ERR("BT read request failed: %d", err);
-        bt_conn_disconnect(conn, BT_HCI_ERR_REMOTE_USER_TERM_CONN);
+        struct bt_gatt_subscribe_params *subscribe_params = &node->subscribe_params;
+        memset(subscribe_params, 0, sizeof(*subscribe_params));
+
+        subscribe_params->notify = tf_uplink_indicate_cb;
+        subscribe_params->value = BT_GATT_CCC_INDICATE;
+        subscribe_params->value_handle = node->attr_handles[GOLIOTH_GATT_ATTR_UPLINK].value;
+        subscribe_params->ccc_handle = node->attr_handles[GOLIOTH_GATT_ATTR_UPLINK].ccc;
+        int err = bt_gatt_subscribe(conn, subscribe_params);
+        if (err)
+        {
+            LOG_ERR("BT subscribe request failed: %d", err);
+            (void) bt_conn_disconnect(conn, BT_HCI_ERR_REMOTE_USER_TERM_CONN);
+        }
+    }
+    else
+    {
+        struct bt_gatt_read_params *read_params = &node->read_params;
+        memset(read_params, 0, sizeof(*read_params));
+
+        read_params->func = tf_uplink_read_cb;
+        read_params->handle_count = 1;
+        read_params->single.handle = node->attr_handles[GOLIOTH_GATT_ATTR_UPLINK].value;
+        int err = bt_gatt_read(conn, read_params);
+        if (err)
+        {
+            LOG_ERR("BT read request failed: %d", err);
+            (void) bt_conn_disconnect(conn, BT_HCI_ERR_REMOTE_USER_TERM_CONN);
+        }
     }
 }